WGU D426 EXAM 2026 Questions and
Answers
A ____ is a column, or group of columns, used to identify a row. - Correct answer-
Primary key
A ____ consists of a single column. - Correct answer-Simple primary key
A ____ key consists of multiple columns. - Correct answer-Composite primary
All primary keys columns are necessary for uniqueness. When any column is
removed, the resulting simple or composite column is no longer unique. - Correct
answer-Minimal
The ____ constraint in the CREATE TABLE statement names the table's ____. The
____ constraint ensures that a column or group of columns is always unique and
non-null. - Correct answer-Primary key
An _____ is a numeric column that is assigned an automatically incrementing
value when a new row is inserted. - Correct answer-Auto-increment column
The ____ keyword defines an auto-increment column. It follows the column's data
type in a CREATE TABLE statement. - Correct answer-AUTO_INCREMENT
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
, A ____ is a column, or group of columns, that refer to a primary key. - Correct
answer-Foreign key
____ requires foreign key values must either be NULL or match some value of the
referenced primary key. - Correct answer-Referential integrity
A ____ constraint is added to a CREATE TABLE statement with the ____ and
REFERENCES keywords. - Correct answer-Foreign key; references
A ____ foreign key is a simple or composite foreign key in which all columns are
NULL. - Correct answer-Fully NULL
____ is a relational rule that requires foreign key values to either be fully NULL or
match some primary key value. - Correct answer-Referential integrity
____ rejects an insert, update, or delete that violates referential integrity. - Correct
answer-RESTRICT
____ sets invalid foreign keys to NULL. - Correct answer-SET NULL
____ sets invalid foreign keys to the foreign key default value. - Correct answer-
SET DEFAULT
____ propagates primary key changes to foreign keys. - Correct answer-
CASCADE
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
Answers
A ____ is a column, or group of columns, used to identify a row. - Correct answer-
Primary key
A ____ consists of a single column. - Correct answer-Simple primary key
A ____ key consists of multiple columns. - Correct answer-Composite primary
All primary keys columns are necessary for uniqueness. When any column is
removed, the resulting simple or composite column is no longer unique. - Correct
answer-Minimal
The ____ constraint in the CREATE TABLE statement names the table's ____. The
____ constraint ensures that a column or group of columns is always unique and
non-null. - Correct answer-Primary key
An _____ is a numeric column that is assigned an automatically incrementing
value when a new row is inserted. - Correct answer-Auto-increment column
The ____ keyword defines an auto-increment column. It follows the column's data
type in a CREATE TABLE statement. - Correct answer-AUTO_INCREMENT
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
, A ____ is a column, or group of columns, that refer to a primary key. - Correct
answer-Foreign key
____ requires foreign key values must either be NULL or match some value of the
referenced primary key. - Correct answer-Referential integrity
A ____ constraint is added to a CREATE TABLE statement with the ____ and
REFERENCES keywords. - Correct answer-Foreign key; references
A ____ foreign key is a simple or composite foreign key in which all columns are
NULL. - Correct answer-Fully NULL
____ is a relational rule that requires foreign key values to either be fully NULL or
match some primary key value. - Correct answer-Referential integrity
____ rejects an insert, update, or delete that violates referential integrity. - Correct
answer-RESTRICT
____ sets invalid foreign keys to NULL. - Correct answer-SET NULL
____ sets invalid foreign keys to the foreign key default value. - Correct answer-
SET DEFAULT
____ propagates primary key changes to foreign keys. - Correct answer-
CASCADE
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
